Apparatus and method for generating oxygen from sodium percarbonate and water, including seawater

Abstract

An apparatus and method generate oxygen gas from sodium percarbonate and water including seawater. The apparatus includes a chamber, a valve system, and an output port. The valve system controls combining a quantity of the sodium percarbonate, a quantity of the water, a quantity of potassium iodide, and optionally a quantity of sodium sulfate decahydrate. A chemical reaction between the sodium percarbonate and the water in the chamber generates oxygen gas, which is output at an output port from the chamber. The potassium iodide is a catalyst for the chemical reaction and optionally the sodium sulfate decahydrate is a temperature moderator for the chemical reaction. A ratio between the water and the sodium percarbonate is in a range of 2.5 to 8 by weight. A ratio of the potassium iodide per liter of the water yields a molarity in a range of 0.25 to 1.25.

We claim: 
     
       1. A method for generating oxygen gas from sodium percarbonate and water comprising:
 combining a first quantity of the sodium percarbonate, a second quantity of the water, a third quantity of potassium iodide, and a fourth quantity of sodium sulfate decahydrate in a chamber, wherein:
 a first ratio of the second quantity to the first quantity is in a first range of 2.5 to 8 by weight between the water and the sodium percarbonate, 
 a second ratio of the third quantity to the second quantity yields a molarity in a second range of 0.25 to 1.25 moles of the potassium iodide per liter of the water, and 
 a third ratio of the fourth quantity to the first quantity is in a third range of greater than zero to 75% of that needed to balance an endothermic heat of dissolution of an adduct of the sodium percarbonate and an endothermic heat of dissociation of the sodium sulfate decahydrate with an exothermic heat of formation of the oxygen gas; 
 
 chemically reacting a chemical reaction between the sodium percarbonate and the water in the chamber, wherein the potassium iodide is a catalyst for the chemical reaction and the sodium sulfate decahydrate is a temperature moderator for the chemical reaction; and 
 outputting the oxygen gas generated from the chemical reaction at an output port from the chamber. 
 
     
     
       2. The method of  claim 1 , wherein the water is selected from the group consisting of seawater, fresh water, deionized water, distilled water, and a mixture thereof. 
     
     
       3. The method of  claim 1 , wherein:
 the water is seawater, and 
 the first ratio of the second quantity to the first quantity is in the first range of 7.0 to 8.0 by weight between the seawater and the sodium percarbonate; and 
 the outputting of the oxygen gas includes outputting the oxygen gas to a fuel cell. 
 
     
     
       4. The method of  claim 1 , wherein:
 the water is deionized water or distilled water, and 
 the first ratio of the second quantity to the first quantity is in the first range of 5.0 to 6.5 by weight between the water and the sodium percarbonate; and 
 the outputting of the oxygen gas includes outputting the oxygen gas at a rate and a temperature less than or equal to a maximum temperature of 44° C. for sustaining human respiration. 
 
     
     
       5. The method of  claim 1 , wherein the third ratio of the fourth quantity to the first quantity is in the third range of 50% to 75% of that needed to balance an endothermic heat of dissolution of an adduct of the sodium percarbonate and an endothermic heat of dissociation of the sodium sulfate decahydrate with an exothermic heat of formation of the oxygen gas. 
     
     
       6. The method of  claim 1 , wherein the combining includes:
 storing the first quantity of the sodium percarbonate and the fourth quantity of the sodium sulfate decahydrate in the chamber in a dry state; and 
 responsive to a demand requesting the oxygen gas, introducing into the chamber a solution of the third quantity of the potassium iodide in the second quantity of the water. 
 
     
     
       7. The method of  claim 6 , wherein the introducing of the solution includes:
 dissolving the third quantity of the potassium iodide in the second quantity of the water to form the solution; and 
 combining the solution with the first quantity of the sodium percarbonate and the fourth quantity of the sodium sulfate decahydrate in the chamber. 
 
     
     
       8. The method of  claim 1 , wherein
 the combining includes:
 storing a mixture of the third quantity of the potassium iodide and a non-zero amount of the fourth quantity of the sodium sulfate decahydrate in a dry state in the chamber that is a first chamber; 
 storing the first quantity of the sodium percarbonate in a dry state in a second chamber; 
 responsive to a demand requesting the oxygen gas, admitting the second quantity of the water into the first chamber to form a solution of the third quantity of the potassium iodide, the fourth quantity of the sodium sulfate decahydrate, and the second quantity of the water in the first chamber; and 
 responsive further to the demand requesting the oxygen gas, metering the sodium percarbonate from the second chamber into the solution in the first chamber; and 
 
 the outputting the oxygen gas includes:
 outputting the oxygen gas generated in the first chamber from the chemical reaction at a gas rate prescribed by a metering rate of the metering of the sodium percarbonate from the second chamber to the first chamber. 
 
 
     
     
       9. A method for generating oxygen gas from sodium percarbonate and seawater, the method comprising
 combining a first quantity of the sodium percarbonate, a second quantity of the seawater, and a third quantity of potassium iodide in a chamber, wherein: 
 a first ratio of the second quantity to the first quantity is in a first range of 2.5 to 8 by weight between the seawater and the sodium percarbonate, and 
 a second ratio of the third quantity to the second quantity yields a molarity in a second range of 0.25 to 1.25 moles of the potassium iodide per liter of the seawater; 
 chemically reacting a chemical reaction between the sodium percarbonate and the seawater in the chamber, wherein the potassium iodide is a catalyst for the chemical reaction; and 
 outputting the oxygen gas generated from the chemical reaction at an output port from the chamber. 
 
     
     
       10. The method of  claim 9 , wherein:
 the first ratio of the second quantity to the first quantity is in the first range of 7.0 to 8.0 by weight between the seawater and the sodium percarbonate; and 
 the outputting of the oxygen gas includes outputting the oxygen gas to a fuel cell.